1. Field of the Invention
The present invention relates to a substrate processing system, a substrate processing method, a sealed container storing apparatus, a program for implementing the substrate processing method, and a storage medium storing the program, and in particular relates to a substrate processing system, a substrate processing method, and a sealed container storing apparatus that use sealed containers each of which houses a predetermined number of substrates, and a program for implementing the substrate processing method, and a storage medium storing the program.
2. Description of the Related Art
When transferring substrates such as semiconductor wafers that are to be subjected to plasma processing such as film formation or etching, this transfer must be carried out in a clean atmosphere so as to prevent attachment of dust to the substrates. Hitherto, substrate processing systems have thus been placed in a room in the whole of which is maintained a clean atmosphere using an air cleaner or the like, for example a “clean room”.
However, in recent years, there have been rapid advances in making the circuitry on semiconductor wafers finer, and hence there has been a rapid increase in the degree of cleanliness required of clean rooms. For example, such refinement of circuitry has reached a level that the size of the dust that must be removed is down to approximately 0.1 μm.
However, with a conventional clean room, increasing the degree of cleanliness to this required level has been difficult from the viewpoints of limits on the air cleaner performance and cost.
There have thus come to be used substrate processing systems according to which, when transferring substrates, a pod that houses a predetermined number of, for example 25, substrates and isolates the housed substrates from the surrounding atmosphere is used, and when the substrates are to be subjected to plasma processing, the substrates are removed from the pod and transferred into a plasma processing apparatus, while dust is prevented from getting into the plasma processing apparatus. According to such a substrate processing system, dust of size approximately 0.1 μm can be prevented from becoming attached to the substrates without increasing the degree of cleanliness of the clean room to the required level described above.
A SMIF (standard mechanical interface) is used as an apparatus for removing the substrates from each pod in such a substrate processing system. As shown in FIG. 9A, such a SMIF 70 is comprised of an enclosure 72 which is a box-shaped sealed station unit that is disposed in front of a cassette chamber (hereinafter referred to as “C/C”) 71 of a plasma processing apparatus (not shown) and communicates with the C/C 71, a pod mounting portion 73 disposed in front of the enclosure 72, and a fan filter unit (not shown) that keeps the atmosphere in the enclosure 72 clean (see “CX-PAL Issue 47”, Sony Corporation, viewed online on Jul. 22, 2004, at URL http://www.sony.co.jp/Products/SC-HP/cx_pal/vol47/pdf/cxeye.pdf).
The pod mounting portion 73 has an upturned-open-box-shaped sliding cover 74 that slides upward as viewed in FIG. 9A, and a pod stage 76 on which a pod 75 is mounted. The enclosure 72 has therein a transfer arm 78 for transferring a substrate cassette 77, described below, between the pod mounting portion 73 and the C/C 71.
According to the SMIF 70, as shown in FIGS. 9B and 9C, when removing substrates from the pod 75, the sliding cover 74 is slid upward so as to lift up a pod cover 79, so that the substrate cassette 77 is separated away from the pod 75. At this time, a space formed between the sliding cover 74 and the pod stage 76 in which the substrate cassette 77 is kept is communicated with the inside of the enclosure 72 via a sliding door (not shown) disposed in front of the enclosure 72, and is thus made clean by the fan filter unit. After that, the transfer arm 78 transfers the substrate cassette 77 on the pod stage 76 into the C/C 71. Moreover, after the substrates have been subjected to the plasma processing and have been housed back in the substrate cassette 77, the substrate cassette 77 is housed back in the pod 75 and then the pod 75 is mounted back on the pod stage 76 by carrying out the reverse procedure to that described above.
However, according to the above substrate processing system, a worker must manually swap a pod 75 mounted on the pod stage 76 housing substrates that have been subjected to the plasma processing (hereinafter referred to as a “processed pod”) with a pod 75 housing unprocessed substrates (hereinafter referred to as an “unprocessed pod”).
In particular, to improve the substrate processing throughput, the processed pod 75 and the unprocessed pod 75 must be swapped over quickly, and hence while the substrate processing system is subjecting substrates to the plasma processing, the worker must wait by the SMIF 70 with the unprocessed pod 75 in hand. However, in recent years, the size of substrates has increased, and hence the weight of a pod 75 has increased, and thus there has been a problem that the burden on workers has increased.
On the other hand, a system may be adopted in which, to avoid such an increase in the burden on workers, the worker does not wait by the SMIF 70. In this case, after a processed pod 75 has been mounted on the pod stage 76, the worker takes out an unprocessed pod 75 from a stocker (not shown) in which a plurality of unprocessed pods 75 are housed, and swaps this unprocessed pod 75 with the processed pod 75. However, in this case, there is a problem that the substrate processing throughput markedly decreases.